Cadmium accumulation and allocation in different cacao cultivars

Area of Science:

• Agricultural Science
• Environmental Science
• Food Safety

Background:

• Cadmium (Cd) is a toxic heavy metal with non-biological essentiality.
• Elevated Cd concentrations in cacao beans exceed European Union regulations, necessitating mitigation strategies.
• Latin American cacao origins are particularly affected by Cd contamination.

Purpose of the Study:

• To investigate inter-cultivar differences in Cd uptake and translocation in cacao.
• To identify cacao cultivars with reduced Cd accumulation in beans.
• To inform strategies for lowering Cd levels in cacao beans for safe consumption.

Main Methods:

• Field study at the CEDEC-JAS cacao cultivar trial in Honduras.
• Analysis of Cd concentrations in soil, rootstocks, scions, leaves, and beans from 11 cacao cultivars.
• Statistical correlation analysis between soil Cd and plant tissue Cd concentrations.

Main Results:

• Soil Cd availability strongly correlated with Cd in rootstocks, scions, and leaves, but weakly with bean Cd.
• Cd concentrations in vegetative parts showed no significant cultivar differences.
• Significant variation in mature bean Cd concentrations was observed among cultivars, not immature beans.

Conclusions:

• Cacao cultivar selection is crucial for managing Cd accumulation in beans.
• Differences in Cd loading during bean maturation, potentially due to xylem-to-phloem transfer, drive cultivar-specific bean Cd levels.
• Selecting cultivars with reduced Cd translocation to beans offers a promising approach for safe cacao production.